For stress values given in Sec.II Part D tables, if there is no any stress value for indicated temp. for example;



100 C 200 C 300 C 400 C

SA....... a b - -



Can designer use b value for 300 or 400 C as given for 200 C, OR he use extrapolation system for 300-400 C which stress value is not indicated, does'nt he?

Extrapolation is not permitted, anyway you don't need extrapolation, as you can't exceed the Max. Temperature Limit on the right end, and Max. Allowable Stress Value at room temp on the left end. Additionally, the latter is not fully true when ULT is used.

What you need is interpolation between points given in the table- this is what you're meant to do.

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Konrad Anikiel